Collapsible loop aerial



Q 1 1 1,614,484 927 M.MATHIESEN COLLAPSIBLE LOOP AERIAL Filed August 1.1925 2 Sheets-Sheet 1 Patented Jan. 18, 1927.

UNITED STATES PATENT OFFICE;

MARIUS MATHIESEN', OF CHICAGO, ILLINOIS, ASSIGNOR T0 MATHIESEN SANDBERGCOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

COLLAPSIBLE L001 AERIAL.

Application filed August 1. 1925. Serial No. 47.562.

My invention relates to improvements in loop aerials for use inconnection with radio apparatus, and has special reference to loopaerials which are collapsible into a minimum space for storage andtransportation.

The object of my invention is to improve and simplify the n'ianufactureof such devices, to provide sin'iple means whereby the turns of the loopcan be readily wound on the frame with less than the final tensionrequire'd and whereby the frame can be easily extended and the turnsproperly tensioned when the device is completed.

A further object of my invention is to produce a multiple turn loop ofthe kind men tioned having a tap or third connecting wire, connected tosubstantially the middle of the aerial wire and accomplishing thislatter in a very simple manner.

Further features and objects of my invention will appear hereinafter.

My invention will be more readily understood by reference to theaccompanying drawings forming part of this specification and in whichFigure 1 is a side elevation of a collapsible loop aerial constructed inaccordance with my invention;

Figure 2, is a fragmentary, vertical sectional view on the line 22 ofFig. 1;

Figure 3, is a fragmentary, vertical sectional view on the line 33 ofFig. 2;

Figure 4, is a fragmentary vertical sectional view on the line 4- 4 ofFig. 1; and

Figure 5. is a horizontal sectional view on the line 5 -5 of Fig. 1.

In said drawings 1 represents a mast which consists of a lower tubularsection 2 and an upper part 3 which is telescopically mounted in thelower part to slide up and down. The upper part or section 3 of the mast1 is shown in F ig. 1, as in its extended position. and it is adaptedwhen the loop is collapsed to slide down into the lower section 2. Themast is adapted to be positioned vertically for use and is adapted to bemounted on a base 4, an upstanding rigid spindle 5 being provided on thebase adapted to enter the lower end of the mast. The mast, or in otherwords the whole loop can be turned on the spindle 5 to best position theaerial for reception.

' At the upper end of the part 3, I provide a rigid cross bar 6 and Iprovide a similar cross bar 7 at the lower end of the part 2.

To complete the frame of the loop I provide laterally extending framearms 8 arranged to be extended outin opposite directions from the middleportion of the mast and provided on their outer ends with rigid crossarms 9.

The several cross arms are notched to re ceive the turnsof the aerialwire 10 which is wound on the arms in a plurality of turns.

In theform of frame illustrated. the wire .10 is wound on the arms 6, 7and 9 in the form of a flat spiral extending in a single layer from endto end of the cross bars except as to some details of winding by which 1am enabled to join a third wire or tap 11 to substantially the center ormiddle portion of the aerial.

In the construction of many radio sets it is desirable to connect theloop aerial to the receiving apparatus not only at each end but also atthe middle thereof.

In winding such a loop as that shown it has proved to be a diflicultmatter to make the winding symmetrical and be able to bring the middleportion of the Winding at the base of the mast in convenient positionfor making a tap.

It is not practicable to make a tap other than at the base of the mastand in forms of winding heretofore used it has not been possible to makethe center tap between an equal number of turns on each side of the mastas the total number of turns with an equal number of notches on eachside of each arm results in the usual straight winding' in an odd numberof complete turns.

lVith an odd number of complete turns the ends of the aerial wire beingmounted oh the lower cross-bar 7 the middle of the wire is at the topcross arm 6 and it is impracticable to connect the third wire to theaerial wire at the top cross arm.

I By means of my. invention I am enabled to provide an equal number ofthe turns 12 on each side of the mast in the form illus-- tra'ted six ofthese turns are thus shown on each side of the mast. Each of the crossarms 6, 'T and 9 are provided with six notches 13 in theouter edge ofeach end of the arm except the lower arm 7 which is provided with sevenof these notches in each end as best shown in Fig. 4.

As best shown in Figs. 4 and 5, I begin winding the aerial wire 10 atone end of the cross bar 7 at preferably the left hand end of the bar asshown in Fig. 4. The beginning end 11 of the wire is secured to the lefthand end of the lower crossbar by a suitable binding post 15 to which isalso secured the flexible connecting wire 16.

The laterally extending arms 8 of the frame are hingedly mounted attheir inner ends to a short section 17 of tubing slidingly mounted onthe upper part 3 of the mast and adapted to permit the part 3 to slidethrough same the mast is collapsed and extended. The normal position ofthe tubular support 17. when the frame is extended is in contact withthe upper end of the lower part 2 of the mar-t as shown in full lines inFig. 1, but during the process of winding the aerial wire 10 on theframe this tubular connection 17 is slid up on the mast a short distancethus drawing in the cross arms 9 slightly. This is to permit the windingon of the aerial wire under less than the final desired tension.

After the loop is completed the several turns are properly tensioned bysliding the tubular connection down into contact with the lower part 2thus forcing the arms 9 outwardly and enlarging the frame to thatextent.

The wire 10 is preferably wound on the arms in a clockwise directionbeginning with the end 14. The opposite end of the first turn enters thesecond notch 18 in the arm 7, and likewise each successive turn advancesinto the next successive notch in the arm until the last or sixth turn19 advances into the seventh notch 20. Instead of carrying the wiredirectly around the frame I provide an auxiliary notch 21 and as bestshown in Fig. 5. I carry the wire 10 back through this notch and acrossthe mast as shown at 22 and then I start to wind the wire 10 on theopposite ends of the cross arms begin ning with the inner notch 23 andending with the seventh notch 9% thus providing six complete turns oneach side of the i'rame. the wire 10 ending at the binding post 28 onthe lower cross bar 7.

I make a connection to the part 22 by soldering thereto a connectingclip 25 and clamping its outer or free end beneath a binding postmounted on a block of insulation material 27 secured to the tubular partot' the mast. 'l'he flexible connecting wire 11 is adapted to be securedin the binding post 26. By this means I am enabled to make a tap orconnect-ion to the exact middle point of the loop wire and make suchconnection at the bottom of the mast.

The mast being made of two pieces 2 and 3 one of. which slides withinthe other I provide latch means for retaining the mast extended. Suchmeans comprises a spring 1r ssed stop Or bolt 29 carried by the upperpart 3 of the mast and adapted to have its outer end 30, which istapered, projected out through an opening 31 in the wall of the lowertubular part 2 of the mast. The bolt 29 and hole 31 are adapted toregister when the mast is fully extended. By forcing the bolt backthrough the opening 31 the mast can be collapsed. In drawing the part 3of the mast out to extend the frame the tubular support 17 is drawn upabove its normal position in contact with the upper end of the lowerpart of the mast and consequently the arms 8 are not fully extended atthis time. This relation of the parts permits the mast to be fullyextended without the necessity of applying any considerable force. Inother words. there is practically no hindrance to the easy extension ofthe mast. After the mast is extended the support 17 can be readilypushed down into contact with the upper end of the lower part 2 of themast the two arms 8 and the support 17 to which they are hinged at 32acting at this time as a powerful toggle lever to enlar e the frame andtension the turns of the wire 10. It should be understood that theseveral turns are fixed in the notches by some suitable means such as adrop of glue at each point of contact.

As many modifications of the invention will readily suggest themselvesto one skilled in the art I do not limit or confine my invention to thespecific details of construction herein shown and described.

I do not herein claim the movable arm carrying member on the mast fortensioning and loosening the turns of wire, such forming thesubject-matter of my co-pending application, il. 11,213, filed February24, 1925.

I claim 1. In a collapsible loop aerial. having a mast and armsprojecting from the mast in a single plane. cross arms on the mast andits arms and forming a frame, an aerial wire having its two ends on thesame cross arm and wound around the frame in an even number of turnsprogressing regidarly across the cross-arms from turn to turn. one halfof the turns being on each side of the must the wire crossing over fromthe last turn on one side to the first. turn on the other side at thecross arm carrying the two ends of the wire. and a tap wire connected tothe aerial wire at said cr ss over portion.

In a collapsible loop aerial. a mast. arms adapted. to be extended atopposite sides of the must to form a frame. cross arms on the mast andthe cross :u'ms. all of the arms having wire receiving openings at theirouter edges for receiving the turns of an aerial wire. an aerial wirewound in the openings beginning at one side and wound in the samedirection clear across, the ends of the aerial wire being secured to thecross arm at the base of the mast. said last mentioned cross arm havingan auxiliary notch in one end adjacent to the mast through which theaerial Wire can be carried back after the innermost turn at one end sothat the innermost turn of the other end can be started in the rightdirection to continue the winding in the same direction.

3. In a collapsible loop aerial, a mast,

adapted to be extended at opposite of the mast, to form a frame, crosson the mast and the arms, all of the arms having wire receiving openingsat their outer edges for receiving the turns of an aerial wire, theopenings in the two ends of the arms being equal in number, an aerialwire wound in the openings beginning at one side and wound in the samedirection arms sides arms clear across, the ends of the aerial wirebeing secured to the cross arm at the base of the mast, said lastmentioned cross arm having an auxiliary notch in one end adjacent to themast through which the aerial wire can be carried. back after theinnermost turn at one end so that the innermost turn of the other endcan he started in the right direction to continue the winding in thesame direction, and a tap wire connected to substantially the middlepoint of the aerial wire.

In testimony whereof, I have hereunto set my hand, this 18th day ofJuly, 1925.

MARIUS MATHIESEN.

